Tag Archives: Telecommunications

Fresh Tech | Intraway Secures DOCSIS

November 23, 2011   Brady   No comments
Intraway DOCSIS Security and Fraud Detection

I first heard of Intraway’s products through a LinkedIn request to talk about DOCSIS security from Intraway’s CEO, Leandro Rzezak. This immediately peaked my interest becuase today our DOCSIS networks are inherently insecure and many are unaware of this. What do I mean by insecure? No, not crying and sniffling in a corner. They are open to theft of service, illegal intercept of the data transmitted, illegal wiretapping of phone calls, etc. Even with Baseline Privacy Interface Specification (BPI+) DOCSIS is quite hackable as evidenced on a number of well known hacking sites. The cool factor in the Fraud & Network Usage Control module offered by Intraway is that they have developed effective algorithms which sit on-top of the most used provisioning systems, Cisco’s CNR and Incognito’s BCC.

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DOCSIS 3.0 Modems Readily Available

June 25, 2011   Brady   1 Comment

If you have been upgraded to DOCSIS 3.0 and were issued a cable modem from your cable provider, you are probably paying a monthly fee for that device. I have always been a strong advocate of owning my own cable modems because it likely pay for itself over the two or three years you own it.

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Undocumented Cisco CMTS Commands

April 20, 2011   Brady   No comments

Every now and then you find a very useful URL. If you are a Cisco CMTS user then you find some of the undocumented commands on this site usefull:

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DOCSIS 3.0 Tutorial – Downstream Channel Bonding

July 18, 2010   Brady   2 Comments

Downstream Channel Bonding is perhaps the ball bearings of DOCSIS 3.0, enabling subscriber data speeds in excess of 160 Mbps (4 times that of previous DOCSIS versions). While conceptually simple, the principle of combining multiple downstream DOCSIS channels together to carry the same user data must have tight constraints in order to preserve the integrity of the data and have the data arrive at the correct subscriber’s device and in sequence. This article will cover both the physical layer aspects and DOCSIS protocol aspects that enable channel bonding.

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DOCSIS 3.0 Tutorial – The EQAM

July 01, 2010   Brady   1 Comment

In my article on DOCSIS 3.0 M-CMTS architecture, I talked about the distributed nature of the CMTS with an M-CMTS core (the CPU of the system), a DOCSIS Timing Server, and an edge Quadrature Amplitude Modulator (EQAM). I am going to cover the EQAM in detail in this article because in the past couple of years, EQAM (also spelled eQAM) has rapidly become part of our vocabulary but its operation and value often go unappreciated. Further, in order to fully understand DOCSIS 3.0 operation, downstream channel bonding, and possible issue which may arise, a thorough understanding of the eQAM is critical.

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DOCSIS and Cable Modems – How it works :: Tutorial Wrap Up

April 20, 2009   Brady   10 Comments
DOCSIS tutorial wrap up

If you have followed the “DOCSIS and Cable Modems – How it works” tutorials this far, congratulations! You now have a basic foundation of how DOCSIS networks operate and the ability to pick up the DOCSIS specification and read and comprehend it – this is hard to do for the novice. If you are just finding this blog for the first time, then I recommend that you go to the DOCSIS Tutorial Series and start at the beginning before proceeding.

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DOCSIS and Cable Modems – How it works :: Station Maintenance

March 03, 2009   Brady   33 Comments
DOCSIS Station Maintenance

While the UCD provides the language of the DOCSIS network, the Station Maintenance messaging is the proverbial “heartbeat” of the DOCSIS network. A station maintenance session consists of a Range Request sent from a cable and a Range Response sent by the CMTS. The CMTS analyzes the signal quality of the Range Request message and sends back any necessary RF adjustments in the Range Response message. This “handshake” between every cable modem and the CMTS must occur once every 30 seconds as dictated by the DOCSIS specification.

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DOCSIS and Cable Modems – How it works :: Anatomy of a Burst

February 22, 2009   Brady   8 Comments
DOCSIS Anatomy of a Burst

Previously I have discussed that cable modems share the upstream channel by using Time Division Multiple Access (TDMA).  This means that when a cable modem is not transmitting data its RF transmitter is turned off.  In order to transmit data it must transmit a burst of data which contains a REQUEST to the CMTS.  The

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Troubleshooting DOCSIS – VoIP Impairments > Delay & Jitter

February 16, 2009   Brady   2 Comments

In this blog I will address delay and jitter as they pertain to VoIP in a DOCSIS network.  Delay, jitter and packet loss are the three primary impairment in a VoIP network, but packet loss was addressed in my Troubleshooting DOCSIS – VoIP Impairments > Packet Loss blog. After packet loss, delay is the second

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Troubleshooting DOCSIS – VoIP Impairments > Packet Loss

February 15, 2009   Brady   No comments

In this blog I am going to focus on VoIP packet loss, which is just one of the three (3) primary types of VoIP impairments that are present in a DOCSIS network. I will cover many RF and IP terms in this blog that I have not discussed in my previous tutorials, not to worry! This terminology is all fodder for future blogs. :-)

To review, the three fundamental impairments which impact call quality of VoIP communications are as follows:

* Packet Loss – The complete or partial loss of a packet containing actual voice payload.

* Delay – The time a packet takes to traverse the space between the source and destination of a voice call. The space is comprised of both the physical distance the data must travel in addition to the active network routing and switching elements, which contribute additional delay.

* Jitter – The variance of inter-packet arrival time from one transmitted packet to the next sequential packet.

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